Differntial fluid pressure motor



MarclI 2, l-9v54 Filed Dec. 14, 1951 l R. D. TOMLIN DIFFERENTIAL FLUID PRESSURE MoToR e sheets-*sheet I J By A ttorney March 2, 1954 R. D. ToMLlN DIFFERENTIAL FLUID PRESSURE MOTOR v2 Sheets-Sheet 2 Filed Dec. 14, 1951 Inventor A ttorney Patented Mar. 2, 1954 DIFFERENTIAL FLUID PRESSURE MOTOR Robert Derrick Tomlin, Harlington, England, as signor to Magnatex Limited, Harlington, England, a British company Application December 14, 1951, Serial No. 261,618

8 Claims. (Cl. 121-97) The present invention relates to diierential fluid pressure motors, and more particularly to suction-operated motors, as used for driving windscreen wipers.

It is the general practice with such motors to arrange for the piston or paddle to move, when the motor is stopped, to a limiting position at one end of its range of movement, so that the Wiper blade will be parked at or beyond the limit of its arc of wiping. Often the piston or paddle is moved a short distance beyond one end of its normal stroke or arc of movement, so that the wiper blade will,be parked outside its normal arc of wiping. This is effected by constructing the manual control valve for the motor so that when it is moved to its off position the source of suction is disconnected from the automatic valve mechanism and is directly connected to one side of the piston or paddle. When in its limiting or parked position, a closure valve carried by the paddle or piston fits against a cup seating surrounding the aperture through which suction is applied, thereby preventing the suction from continuously acting on the piston or paddle packings during parking.

In some wiper installations it is necessary for the wiper to park on the right-hand side and in others on the left-hand side, and this necessitates special motor constructions for each application.

The present invention has for an object to provide a fluid pressure motor of which the piston or paddle can be parked at either one side or the other.

The specification of my copending application Serial No. 209,822 filed February 7, 1951, describes an arrangement for achieving this result by leading the passages connecting with the outlet ports of the automatic valve to ports in the valve seating associated with the manual control valve which is so constructed that in its on position it connects these ports to opposite sides of the motor whilst when in one or the other of two off positions it connects either one side or the other of the motor directly to the source of suction whereby the paddle will be parked on that side. I

The motor described in that specification employs a'manual control valve arrangement which may involve special fitting when the motor is to i be iitted as a replacement for an existing motor which is constructed for right-hand or left-hand parking only. This particularly applies inthe case of the smaller types of suction motor in which the manual control valve is arranged for l 2 sliding movement in a direction parallel to the motor spindle and to either one side or the other of the centre of the motor cover depending upon the side to which the paddle is to be parked.

A further object of the present invention is to provide a differential `fluid pressure motor of which the piston or paddle can be parked at either one side or the other, and which is so constructed that it can be used as a replacement for existing motors constructed for parking at only one side or the other.

Moreover, in order to comply with the design requirements of different car manufacturers, the windscreen wiper motors have to be built with different lengths of driving shaft, different lengths of bushings through which this shaft passes, and different head fittings on the shaft. Thus a stockist of replacement motors has to carry a stock of several motors with different lengths of shaft and bushing, and different head fittings in order to meet all the requirements which may be placed upon him.

A still further object of the invention, therefore, is to provide a motor of which the driving shaft and bushing are readily interchangeable, whereby a stockist may fit the requisite shaft and bushing to a standardised motor unit to pro-v duce the desired motor.

According to the invention, the motor is provided with two manual control valve seatings, the valve seatings having ports therein which are so connected to the motor chamber, the source of suction and the automatic valve that each valve seating, when associated with a control valve, is adapted to effect starting and stop ping of the motor and to park the paddle at the corresponding side of the motor, a control valve being associated with either one or other of the valve seatings depending upon the side to which the paddle is to be parked, whilst the second valve seating is associated with a member for connecting together the ports thereof leading respectively to the corresponding side of the motor and the corresponding outlet port of the automatic valve. The member associated With the second valve seating may also comprise a control valve which is left in its on position. To change the parking position it is then only necessary to connect one or other of the control valves for manual operation, the other control valve being left in its on position. Means may be provided for locking or holding the appropriate control valve in its on position.

Alternatively, the member associated with the second valve seating may comprise a special member which is simply secured in position, this member and the control valve being interchangeable to select the side of the motor at which the piston or paddle is to be parked.

The invention also consists in a suction motor of the oscillating paddle type wherein the motor cover is provided with two control valve seatings disposed at opposite sides of t-he centre of the cover, each valve seating having ports leading respectively to a connection for a source of suction and to the inlet port of the automatic valve, the outlet ports of the automatic valve being con. nected respectively to ports in the respective valve seatings which are also provided with further ports connecting respectively with the corresponding sides of the motor, and wherein a control valve is provided which is tted to one valve seating and is formed with ports or passages which, when the valve is in its on position, it connects the source of suction to the central inlet port of the automatic valve and the associated outlet port of the automatic valve to the corresponding side of the motor, and in its off position, disconnects the source of suction from the inlet port of the automatic valve and directly connects the source of suction to the corresponding side of the motor, and wherein a further member is provided which is tted to the other of the valve seating and connects the associated outlet port of the automatic valve to the corresponding side of the motor.

According to a further feature of the invention, the motor is constructed with a socket portion for receiving the end of the bushing, said socket portion surrounding theend of the motor shaft and being constructed of; two or more parts which can be separated without otherwise disassembling the motor, the bushing being provided with an enlargement at its end which is adapted to fit into a corresponding recess in the socket s portion so that the bushing will be retained therein against longitudinal movement when the socket parts are assembled around the bushing end, there being iitted within the bushing an extension shaft, the end of which is adapted to interengage or couple with the end of the motor shaft when the bushing, with the extension shaft therein, is secured in position.

In carrying out the invention, the motor can be constructed as a conventional paddle type motor except that two manual control valve seatings are provided which are disposed on opposite sides of the centre of the cover, the two outlet ports from the automatic valve leading to their corresponding sides of the motor through ports in that one of the valve seatings located onl the corresponding side of the cover. Thus, both said outlet ports lead to their corresponding sides of the motor through portsin one or other of the control valve seatings.

In one embodiment, only a single manual control valve is, provided which may be tted selectively to either one or other of the valve seatings depending upon the side to which it is desired that the paddle should park, the other valve seating being fitted with a fixed member provided with a passage for connecting the associated outlet port from the automatic valve to the corresponding side of the motor, said member also seating over and preventing air leakage to the port leading to the inlet portV of the automatic valve. The control valve and fixed member are interchangeable to select the side of the motor at which the paddle is to be parked.

In another embodiment, each valvev seating is iii tted with a conventional control valve movable between on and oi`f" positions. By leaving one control valve permanently in the "on position, the motor can be started and stopped by moving the other control valve, the paddle parking on the same side of the motor as the actuated control valve when it is moved to its off position.

The control valve which is permanently in the on position permanently connects that side or' the motor to the corresponding outlet port of the automatic valve, whilst the movable control valve either, in its on position, connects the suction supply to the inlet port of the automatic valve and the adjacent end or" the motor to the corresponding outlet port oi the automatic valve or, in its off position, directly connects the source of suction to the adjacent end of the motor and simultaneously uncovers the port in the valve seating leading to the inlet port of the automatic valve so that this inlet port is connected to the atmosphere. The opposite end of the motor will therefore be vented to atmosphere irrespective of the position of the automatic control valve.

Only that control valve which is to be moved need be iitted with a handle or lilze member for manual operation; preferably the other control valve is associated with means for holding it in its on position. For example each control valve may be provided with a spigot adapted to be engaged with a slidable manual control member. This control member may be provided with an extension piece such as a rod carrying the operating knob, this extension piece being interchangeable from one control member to the other depending upon which valve is to be operated; The control member not fitted with the extension piece may be locked in position by a screw or in any other convenient manner. Alternatively, only one of the control members may be provided with slots so that it is slidable relative to the screws holding the valve assembly in position, the other control valve having its spigot engaging with a fixed member which may be similar to a control member but without the slots for permitting sliding movement, this xed member having apertures through which the assembly screws pass and thereby hold the associated control valve on its on position. The fixed member and slidable control member are interchangeable to select the side to which the paddle is to be parked.

Each control valve seating may be associated with a separate suction supply connection, that which is not in use being sealed off for example the motor may be provided with a threaded tubular connector or nipple and a threaded plug which may be interchangeably fitted in threaded apertures in the casting leading respectively to the suction supply ports in the respective valve seatings.

The passages leadingr from the valve seatings to opposite sides of the motor preferably terminate in two cup seatings arranged on the underside of the cover and adapted to cci-operate respectively with closure 0r scaling members carried from opposite sides or" the paddle so that when the motor is a parked position, the source of suction acts on a closure member and does not act continuously on the paddle packings.

In order to provide for the interchangeable extensionshaft and bushing, the top cover of the motor housing is made with the half socket por.- tionthereof which surrounds the shaft bushing separate from the remainder of the cover and secured thereto, or to the bottom half of the motor housing, by means of screws or the like. The motor shaft projecting from the paddle is made of reduced length, its end terminating short of the recess adapted to receive the enlarged collar at the end of the shaft bushing, and being formed with flats or with a transverse slot or ridge adapted to engage with a corresponding socket or with a ridge or slot in the end of an extension shaft carried in the bushing. This extension shaft is preferably captive in the bushing, so that when a bushing is fitted to the motor housing with its collar` in the recess, the end of the extension shaft will be automatically coupled with the end of the motor shaft. By securing the half-socketv portion of the cover in position the bushing will be retained with the motor shaft and extension shaft coupled together. The collar on the bushing is preferably of polygonal form so that when the cover halfsocket portion is screwed down it will lock the bushing against rotary as well as longitudinal movement.

With the construction described, it will be appreciated that bushings of different lengths and extension shaft of different length and with different end ttings may be interchangeably mounted in'and secured to the motor housing without it being necessary for the motor cover` to be removed.

In order that the invention may be clearly understood, embodiments thereof will now be described by way of example with reference to the accompanying drawings in which:

Fig. 1 is a perspective view of a suction operated windscreen wiper motor embodying the invention,

Fig. 2 is a front elevation'of the motor with the automatic valve cover plate removed,

Fig. 2a is a perspective view of the movable element of the automatic valve sh-owing the reverse face to that visible in Fig. 2,

Fig. 3 is a plan view of the motor with the elements of the control valve and fixed member removed so as to show the control valve seatings,

Fig. 4 is an exploded perspective view of the operative control valve shown on the right hand side of the motor shown in Fig. 2,

Fig. 4a is a perspective view of the control valve element showing the under face thereof,

Fig. 5 is a perspective view of the control valve seating and xed member shown on the left hand side of the motor in Fig. 1,

Fig. 5a is a perspective View of the fixed member shown in Fig. 5 but showing the reverse face thereof, y

Fig. 6 is a perspective view of a control valve with the cover removed and having a screw for locking the control valve in the on position,

Fig. 7 is a perspective view of a modified valve construction which is held permanently in the on position,

Fig. 8 is an exploded perspective view of the Ybushing and detachable extension shaft to which the wiper blade is attached,

Fi-g. 8a is a perspective view of one of the elements shown in Fig. 8 and showing the opposite face thereof, and

Fig. 9 is a sectional View of the detachable eX- tension shaft and bushing shown in Fig. 8.

The motor illustrated in the drawings is a suction operated windscreen wiper motor which is basically of known design and comprises a casing I tted with a cover 2 forming a sealed piston chamber in which a piston 3 of the paddle type oscillates a rocker shaft 4 having anextension 4a which drives a wiper blade, the paddle dividing the chamber in an air-tight manner into two compartments. Y

The cover 2 is provided with aligned passages 5 and 6 (Fig. 3) leading to control valve seatings 1 and 8 at opposite ends of the motor by means of which the passages 5 and 6 can be put into communication with suction supply conduits 9 and I0 respectively as will hereinafter appear. Either of these suction supply conduits can be connected to a source of suction such as the intake manifold of an internal combustion engine. In Figs. 1 and 3 conduit I 0 is fitted with a detachable screw threaded nipple II for connection to the suction source and conduit 9 is sealed by means of a screw threaded plug I2. Nipple II and plug I2 are interchangeable according to which side of the motor it is desired that the wiper blade should park.

The passages 5 and 6 lead to automatic valve mechanism indicated generally at I 3 for connecting the source of suction to opposite sides of the paddle in order to reciprocate the paddle, the

.- valve mechanism also controlling the admission of atmospheric air to the side of the paddle not for the time being under suction. The valve mechanism I3 is made automatic in action under control of the swinging movement of the paddle so that the valve mechanism is automatically reversed each time the paddle reaches the limit of its normal swing in each direction. In the embodiment shown, this automatic valve mechanism is of known construction comprising a semirotary disc valve I4 (Figs. 1, 2, 2a and 3) of segmental form having an arcuate channel I5 therein and movable in an arc between two positions by means of a snap action mechanism embodying a rocker I6 actuated by a ilat on the rocker shaft 4. The valve operates against a surface I1 (Fig. 2) of the cover 2 having three valve ports I8, I9 and 20 disposed in an are therein so as to cooperate with the channel I 5 in the valve IB. The details of this automatic valve mechanism are known and form no part of this invention, and will not therefore be described in detail. It need only be mentioned that the valve I4 always covers the middle port I9 and is operated so as also to cover the ports I8 and 20 alternately and thereby effect communication of the ports i8 and 20 alternately with the port I9 by way of the channel I5 in the valve. The ports I8 and 20 are each open to the atmosphere when not covered bythe valve. The port I9 leads into the passages 5 and B, while the port I8 leads into a passage 2| which communicates through ports in the left hand control valve seating with a passage 22 which leads to the piston chamber on one side of the paddle within a cup seating 23. The port 20 leads into a passage 24 which communicates through ports in the right hand control valve seating with a passage 25 leading to the piston chamber on the other side of the paddle within a cup seating 28. The paddle is provided with sealing closures 2l and 28 arranged to co-operate with the cup seatings 23 and 25 respectively when suction is continuously' applied to one of those seatings so that the suction is operative to hold the closure in sealing contact with the cup seating and with the wiper blade parked on the corresponding side of the motor according to the selected arrangement of the control valves.

The passages 6, ill, 2s and 25 terminate in ports Sa, Illa, 24a and 25a in the valve seating 8 which is cast integrally with the cover 2 and with which l claim: l. A differential fluid pressure motor compris ing a housing, a paddle mounted for oscillatory movement within the housing, a rst valve seating on the housing having an inlet port and rst and second outlet ports, an autom-atie valve member movable over said first valve seating by the movement of said paddle and having a passage therein arranged to connect said inlet port -alternately to sai-d outlet ports, a second valve seating on said housing having a port connecting with said inlet port, a port connecting with said first outlet port, a port connectable to a source of supply of fiuid at other than atmospheric pressure and a port leading into the housing at one side of the paddle, a third valve seating on said housing having a port connecting with said inlet port, a port connecting with said second outlet port, a port connectable to a source of supply oi fiuid at other than atmospheric pressure and a port leading into the housing at the other side of the paddle, a manually operable valve member movable over one of said second and third valve seatings between an on position and an off position and having a first passage therein arranged to connect the associated port connectable to the source of fluid supply to, in the on position, the associated port connected to said inlet port and, in the oli position, to the associated port leading into the housing, and said manually operable valve member having a second passage therein arranged to connect the associated port leading into the housing to, in the on position, the associated port connected to an outlet port and to disconnect said ports in the off position, and a fluid conducting member mounted on the other of said second and third valve seatings and connecting the port therein which is connected to one of said outlet ports to the port therein leading into the housing.

2. A differential fluid pressure motor comprising a housing, a paddle mounted vfor oscillatory movement within the housing, a first valve seating on the housing having an inlet port and first and second outlet ports, an automatic valve member movable over said first valve seating by the movement of said paddle and having a passage therein arranged to connect said inlet port alternately to said outlet ports, a second valve seating on said housing having a port connecting with said inlet port, a port connecting with said first outlet port, a port connectable to a source of supply of fluid at other than atmospheric pressure and a port leading into the housing at one side of the paddle, a third valve seating on said housing having a port connecting with said inlet port, a port connecting with said second outlet port, a port connectable to a source of supply of fiuid at other than atmospheric pressure and a port leading into the housing at the other side of the paddle, a manually operable valve member movable over one of said second and third valve seatings between an on position and an off position and having a first passage therein arranged to connect the associated port connectable to the source of fluid supply to, in the on position, the associated port connected to said inlet port and, in the off position, to the associated port leading into the housing, and said manually operable, valve member having a second passage therein arranged to connect the associated port leading into the housing to, in the on position the associated port connected to an outlet po-rt and to disconnect said ports in the off position, and a fluid conducting member fixed on the other Aof said second and third valve seatings and connecting the port therein which is connected to one of said outlet ports to the port therein leading into the housing, said fluid conducting member also seating over and preventing fluid leakage through the associated port leading to said inlet port, and said manually operable valve member and said iiuid conducting member being interchangeable to select the side of the motor at which the paddle is to be parked.

3. A differential fiuid pressure motor comprising a housing, a paddle mounted for oscillatory movement within the housing, a first valve seating on the housing havin-g an inlet port and first and second outlet ports, an automatic valve member movable over said first valve seating by the movement of said paddle and having a passage therein arranged to connect said inlet port alternately to said outlet ports, a second valve seating on said housing having a port connecting with said inlet port, a port connecting with said first outlet port, a port connectable to a source of supply of iiuid at other than atmospheric pressure and a port leading into the housing at one side of the paddle, a third valve seating on said housing having a port connecting with said inlet port, a, port connecting with said second outlet port, a port connectable to a source of supply of fluid at other than atmospheric pressure and a port leading into the housing at the other side of the paddle, a manually operable valve member movable over one of said second and third valve seatings between an on position and an ofi' position and having a rst passage therein arranged to connect the associated port connectable to the source of fluid supply to, in the on position, the associated port connected to said inlet port and, in the off position, to the associated port leading into the housing, and said manually operable valve member having a second passage therein arranged to connect the associated port leading into the housing to, in the on position, the associated .port connected to an outlet port and to disconnect said ports in the off position, and a fluid conducting member of resilient material fixed over the other of said second and third valve seatings and connecting the port therein which is connected to one of said outlet .ports to the port therein leading into the housing, said fluid conducting member also seating over and preventing fluid leakage through the port leading to said inlet port.

4. A differential fluid pressure motor comprising a housing, a paddle mounted for oscillatory movement within the housing, a first valve seating on the housing having an inlet port and first and second outlet ports, an automatic valve member movable over said first valve seating by the movement of said paddle and having a passage therein arranged to connect said inlet port a1- ternately to said outlet ports, a second valve seating on said housing having a port connecting with said inlet port, a port connecting with said first outlet port, a port connectable to a source of supply of fluid at other than atmospheric pressure and a port leading into the housing at one side of the paddle, a third valve seating on said housing having a port connecting with said inlet port, a port connecting with said second outlet port, a port connectable to a source of suply of fiuid at other than atmospheric pressure and a port leading into the housing at the other side of the paddle, and two manually operable valve members respectively associated 1'1 with and movable over each of said second and third valve seatings between an on position and an off position, each manually operable valve member having a first passage therein arranged to connect the associated port connectable to the source of fluid supply to, in the on position, the associated port connected to said inlet port and, in the oil position, to the associated port leading into the housing, and also having a second passage therein arranged to connect the associated port leading into the housing to, in the on position the assooiatedport connected to an outlet port and to disconnect said ports in the olf position.

5. Motor as claimed in claim d, comprising also operating .means selectively connectable to either one of said manually operable valve members,.and means securing the other of said manually operable valve members in its on position.

:6. Motor as claimed in claim 5, wherein each oi said second and third valve seatings has a threaded aperture, and a screw screwable into either of said `threaded apertures according to which oi the manually operable valve members is kto beheld in the on position, said apertures being so located that said screw holds the associated manually operable valve member inthe on position.

'1. A differential fluidpressure motor compris- ,ing a housing, a paddle mounted for oscillatory movement Within the housing, a first valve seatingon the housing having an inlet port and iirst and second Voutlet' ports, anautomatic valve member movable over said .first .valve seating by the movement of said paddle land having a passage therein arranged to connect said inlet port alternately to said outlet ports, a second valve seating on said housing .havingaport connecting with said inlet port, a port connecting with said first outlet port, a port connectable to a source of supply of fluid at other than atmospheric pressure Yand a port leading into the housing at-one side of the paddle, a third valve seat- :ilgion Said housing having aportconnecting with said inlet port, a port connecting withsaidsecrond outlet port, a port connectable to a source of supply of nuid at other than atmospheric pressure and a port'leading into vthe housing at the -other side of the paddle, two manually operable valve members respectively associated with and movable over each oi said second and third valve seatings between an on position and an off position, each manually operable valve member .having ka iirst passage therein arranged to con- -nect the associated port connectable to the source of iiuid supply to, inthe on position, the associated port connected to said inlet port and, in .the oii position, to the associated port lead- .ing into the housing and also having a second passage therein arranged ,to connect the associated port leading into the 'housing to, in the on .position the associated ,port @connected to Yan outlet port and to disconnect said ports inthe on position, a cover for each of Vsaid manually .operable valve members, means for holding each cover to its associated valve seating, a slidable roperating member operativelyconnected `to one of said manually operable valve members, andfa non-sliding member apertured to permit :the passage therethrough of the associated .cover Vholding means in non-sliding relation and. op-

eratively connected A'to the other manually operable v,valve lmember .to hold it permanently .in ,the

.on position, said slidable operating 'member andsaid non-sliding Amember being interchangeable to select the side oi `the motor at which 4:the paddle is to be parked.

8. A diierential iluid pressure :motor comprising aLhousing, la paddle mounted for oscillatory movement Within the housing, a first valve seating on .the housinghaving an inlet port'and rst and second outlet-ports, an automaticvalve member movable over said rst valve seating by .the movement of said'paddle and having a passage therein arranged .to connect said inlet Aportzal- .ternately vto said outlet ports, a second valve seating on said housing having a port connectwith said second outlet port, a port leading :to

a second inletconduitin the housing anda port .leading into the housing at the other side vof lthe paddle, Aa sealing plug inone of said `inlet conduits and a connecting rmember'in the other .conduit for Vconnecting the motor to a source .of

supply of 'duid at other than atmospheric pressure, a manually opera'ble .valve member movable over the valve seating associated with the `connecting memberbetween an on'position andan oli position and .having a rst `passage therein Aarranged to connect the associated port leading to the connecting member to, inthe on position, the `associated port connected to said inlet port and, in the off position, to the associated port `leading into .the housing, and said manually operable vvalve member having a second passage ltherein arranged to connect the associated port leading into the housing to, in the oniposition vthe associated .port connected to an outlet port `and to .disconnect said ports in the off posistion, and a 4iiuid conductingimember mounted on .the valve seating associated with the sealing plug and connecting the port therein which .is connected vto one -oi said outlet ports tothe port therein leading into the housing, said manually operable valve member and said connecting-member .being interchangeable .respectively with said fluid conducting member and said sealing plug. ROBERT DERRICK TOMLXN.

References Cited in the file of this patent 'UNITED lSTii'IllS PATENTS Number Name Date '1,629,949 C'aarello lMay v2li, 1927 '2,298,734 'Buchmann Oct. 13, 1942 

